Making CreateProcess inherit the console of the calling process
When I call CreateProcess in Windows, the new process doesn't seem to inherit the console of the calling process. I made a test program that runs "ruby xtest", xtest being a script that writes "hello" to standard output. I ran this test program from Emacs, and get no output. I also tried the following code calling GetStdHandle, but again, no output. Then I tried passing CREATE_NEW_CONSOLE in dwCreationFlags to CreateProcess, which made a whole new window with the Ruby output. Finally, I made a simple fork/exec test program and compiled it using Cygwin's GCC. This program worked: the Ruby output showed up in Emacs as expected. I tried to decipher the Cygwin source code in http://cygwin.com/cgi-bin/cvsweb.cgi/src/winsup/cygwin/spawn.cc?rev=1.268&content-type=text/x-cvsweb-markup&cvsroot=src but failed. So, how do you make the new process inherit the console of the parent process such that the output from the child shows up as expected?
STARTUPINFO si;
PROCESS_INFORMATION pi;
memset(&si, 0, sizeof(si));
memset(&pi, 0, sizeof(pi));
si.dwFlags |= STARTF_USESTDHANDLES;
si.hStdInput = GetStdHandle(STD_INPUT_HANDLE);
si.hStdOutput = GetStdHandle(STD_OUTPUT_HANDLE);
si.hStdError = GetStdHandle(STD_ERROR_HANDLE);
if(!CreateProcess(0, "ruby xtest", 0, 0, 1, 0, 0, 0, &si, &pi)) die("CreateProcess");
Answer
I know, this thread is rather old, however, I just ran into the same problem.
Just as for the TS, the console handle was inherited and working fine under Cygwin, but not on a Windows console. Instead, the output on stdout was neither shown, nor any error was reported. Inherited Pipe handles worked still fine.
I took me some time to identify the (now obvious) problem: CreateProcess() was called with CREATE_NO_WINDOW. Dropping this flag, console output is fine. (Though, according to the code of the TS, they never set this flag in the first place.)
Hope this might be helpful for people who also stumble across this thread, like myself.